View Full Version : Will a 2nd Fan on top of my CPU Heatsink and Fan Help or make it worse?
:confused: I want to overclock my Athlon XP. I have got an all Copper Heatsink with a 7200RPM Fan on the XP. I would like to know if I attach another fan on top of the original fan would that help cool the CPU better or make it worse. (Obviously, the fan will be the same speed: 7200RPM, and will be blowing in the same direction.)
Even if the double fan theory doesn't work out, I also have another idea. If I attach a flexible metal tube (I don't know what they call them) to the end of the CPU fan and direct it to a hole in the back of my case (so the CPUs heat goes outside instead of heating the whole system temperature) will it cool the CPU better or make it worse. I'm not sure if it makes it longer for the CPU heat to escape or not??? Also, instead of making a double fan, would it be better just to attach the tube to the end of the CPU fan and direct it to a hole back of the case and attach a fan to the hole at the back of the computer to force out air from the CPU tube??? Your Help and Suggestions Are Appreciated!
Thank You.
(I have attached a pic of what I mean by tube, this is not my system, it is off overclockers.com)
Sorry I forgot to attach the pic
Well I'm not sure about your double fan idea, but using a duct is great! One thing to remeber when making your duct is to try to make as few curves in it as possible (so that air resistance is decreased). Most people just cut a hole in the side of their case and attach the duct there. One other thing I've seen is them cutting a hole in the side of the case and just mounting a fan on the side of the case, letting it blow onto the CPU...
JigPu
So are you saying that directing that tube straight out the side of case is better than the rear of my case? Because I would prefer to make a hole in the rear instead of the side??? I am basically going to do the same thing as the picture except I wont be blowing air onto the CPU. I will let the heatsink and fan operate normally but I will put the tube on it as shown in the pic (except it will obviously be a SocketA/462). And on the rear of my case where the tube is going to come out, I will add another fan to increase air output. Will that cool the CPU better than leaving it normal?
Thanks Again JigPu. :)
I wouldent use the metal duct.Go non conductive material.
I would also have the heat sink fan pull outside air in,unless you have great case cooling.
Lastly installing a duct really adds cooling to the processor.I am sold on it.Have 2 ducts on my system that keep my dual XP1800 at 39c and thay are running at 138x11.5
SickBoy
01-29-02, 12:52 PM
I have a duct (cardboard) from my case side (not the back like in the pic, the side) down on to my CPU HSF. I have a 44 CFM Delta pushing air onto the HSF. It's a very good idea. works well.
Stacking fans doesn't help. In fact, it hurts. Avoid it.
Hers are custom home made ducts really lowered my temps/
I am now going to remove my delta screamers and Install 2 92mm 50 cfm fams on the ends of these ducts.If this works I will save bigtime on the noise !!
Firstly, I'd like to thank everyone for their suggestions.
But, I don't really want to make a duct. I just want let the heatsink and fan on the CPU blow out the normal way but I will put a tube around the fan and direct it outside the case. And if necessary, I will put an extra fan on the end of the tube on the outside of the case, to pull more air out of the tube.
Could you experts please tell me if this will help cool the CPU better or worse?
Thanks
muddocktor
01-29-02, 11:30 PM
It should help in cooling both your proc and the case in general as you will be blowing out the highest source of heat in the case. I say go for it, man. I would use an extra fan at the end of the duct to help remove the hot air, like you were talking about.
i see noise is not a factor with ur system so if i was u i would load the ****er up with fans :D or just dump them all and save big with water cooling.. it will take more time but overclocking is a hobby right ;).. i will be doing watercooling but i find my self not ready yet.. but as soon as my alpha is not enough i will do watercooling :D or whatever is best at that time :D
ButcherUK
01-30-02, 02:40 AM
Originally posted by ToF
But, I don't really want to make a duct. I just want let the heatsink and fan on the CPU blow out the normal way but I will put a tube around the fan and direct it outside the case.
Um that is a duct... It should help. As for a second fan - probably not worth it, if you have one spare try it.
I can't remember what thread it was in, but stacking fans has been talked about & to summarize: stacking fans will not increase the volume of air. It will increase the pressure & some have suggested that it will cause at least 1 of the fans to rotate faster & shorten it's lifespan.
Thank You Everyone for your help and suggestions.
I believe you have cleared this issue for me.
Thanks!!! :cool:
Koooler King
01-31-02, 11:36 AM
Originally posted by nodoze
I can't remember what thread it was in, but stacking fans has been talked about & to summarize: stacking fans will not increase the volume of air. It will increase the pressure & some have suggested that it will cause at least 1 of the fans to rotate faster & shorten it's lifespan.
Good point. I've played with and tested this idea ... nodoze is right on ... in free-flow without a heat sink, the net air flow is the same with (2) stacked fans as with (1) ... you get the max flow shown on the fan performance curves for each fan, and in series what exits one, simply enters the other, so no difference. However, depending on the heat sink, there will be a certain amount of pressure drop due to air flow resistance. In that case, the (2) fans can deliver twice the pressure potential as a single fan. Depending on the fan curves, the greater pressure potential will move the operating point on the curve and give an increase in air flow ... it won't be even close to double, but it will increase some. As for noise, it will go up by 3 dB(A) with (2) fans over one of the same model. One problem, maybe related to what nodoze mentioned on fan speed changes, (2) fans at nearly the same speed, can create annoying beat frequencies and harmonics as their speeds fluctuate, which can exceed the expected 3 dB(A) noise increase.
Bottom line, go with the more elegant duct solution, or if your fan is a 25mm deep model, consider one that is 38mm deep. Good luck.
Koooler King
Ottoman
01-31-02, 12:08 PM
If u are to stack fans, u have to make them rotate in opposite directions..
ie. bottom one clockwise, top one counter clockwise..
much like the dual rotor choppers
Stacking fans only helps to overcome static pressure. THat may or may not be an issue depending on your heatsink. However, once you put in a duct, particularly a long curved one such as in your picture, then you increase the static pressure. In such a case, having a fan at each end can really help. Also, in such a case you don't need to have them spinning in opposite directions as the airflow has a chance to even out over the length of the duct.
nihili
UserName
01-31-02, 12:58 PM
I an gonna guess and say you have the tube(duct) set up that way cause you want to get the hot air out of the case.
I suggest you turn the rear case fan around and attach the duct (tube to the other side of your heat sink. Also turn the front fan around.
This will be a better cooling setup and if you dont get a 3C drop or more i will give you 10 dollars.
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